Walter Lindekens

Roger, this drawing out of AP1600A might be helpful. Don't know how precise or to scale it is but the illustrations in the RAF Air Publications tend to be rather good. Cheers, Walter

Regarding those propellers, as already mentioned in this fascinating thread, AP1600A Vol I quotes the Manchester I props as deHavilland variable-pitch, hydromatic group, D.I.S.27, type 6/3. Sadly, unlike most other AP's I have, the one for the Manchester does not quote the prop diameter. However, here is a link to a 2017 thread on DH propellers on the Key Aviation Form (when that was still a thriving place...): https://www.key.aero/forum/historic-aviation/146954-de-havilland-decoder-part-one It takes a bit of reading but at one stage one of the participants states: DP456250A is listed as being fitted to the Manchester I, fitted with a Vulture II engine. DP456250A would be the identification number of the blade used. And two posts higher in that thread the diameter of the DP456250A is quoted as 16' 0". Might be worth to have a go at entering that 16' diameter on your drawing and see how it compares to the photograph. Cheers, Walter

I've been wondering about balloon cables and props too, Graham. But seeing that all aircraft equipped with these cutters had a number of them in the part of the leading edge that is covered by the propeller arc(s) one would assume some cables could get past the prop in some cases. NA file AIR 14/1489 "Balloon Cable Cutters" has lots of interesting documents on the subject though not related to any specific aircraft type. The oldest document in the file, titled Martin Cartridge Fired Cable Cutters for Aircraft Protection and which covers instructions for fitting and handling the device is actually dated 03 June 1940 so they were available fairly early in the war. As for night ops, the Blenheim Mk IV Rotterdam raid I mentioned in my earlier post was a daytime raid. I suppose that if crews had to attack a target defended by a balloon barrage, negotiating the cables would be equally hazardous by day as by night. Cheers, Walter

Frankly, I have my doubts about that "wedge" being an anti wing root stall device... I mean, if it were an important modification to improve the aircraft's flying characteristics then it's use would have been much more wide spread. And there are a great many photo's of Mk IV's out there without the wedges. I have yet to find documentary proof but I'm pretty sure that the wedge is in fact a cable deflector and mounted on Blenheim IV and V aircraft that are fitted with balloon cable cutters. On these aircraft there is one cutter near the fuselage and one near the engine nacelle on the inner wing section, and some more on the outer wing. Any ballon cable brushing against the side of the nose would become lodged in the corner where fuselage and wing meet. A triangular wedge would neatly lead that cable into the cutter. Many, if not all, photos of Mk IV's and V's that show the wedge also show these aircraft to be fitted with cable cutters. These cutters are installed in "containers" that are mounted into the wing leading edge. When installed the cutters protrude beyond the leading edge, obviously, but when the cutters are not fitted the containers are closed with a blanking plate. I think such a blanking plate is shown in the photo in @TISO yesterday's post. The photo in the Profile on the Mk IV, on page 171 that @Ed Russell refers to clearly shows the cable cutter fixed next to the wedge. And the web is full of photo's of 13 OTU's FV-B, serial V6083 which clearly shows balloon cable cutters in conjunction with the wedges. Here's a link to one of the many: https://www.worldwarphotos.info/gallery/uk/raf/blenheim/blenheim-iv-v6083-13-otu/ . Early MK V's would appear to have the cable cutter set up as a standard fit, as AP1530C Vol I, the air publication covering the Mk V in detail, actually states: Quote Early aircraft have barrage cable protection plates fitted to the leading edge of the main plane except in way of the oil cooler air intakes, the wing gun door and the landing lamps. Thirteen containers are welded to the protection plates to take the cable cutter units, eight to port and five to starboard. Three of the cable cutter units are double headed, one being fitted on each side of the fuselage, and one nearly midway between the starboard nacelle and the wing tip, the remaining ten are single headed. Leading edge cable cutters are described in AP2051 A Vol I. Unquote The wedge, sadly is note mentioned in that para, nor anywhere else in AP1530C, some illustrations show it and some don't. As for the Mk IV, earliest mention of balloon cable cutters I've come accross so far is in an account of the 16.07.1941 raid on Rotterdam. I'll be happy to be proven wrong but "Smudge" Smith, president of the Bristol Blenheim Society shares my opinion and he knows a fair bit about the Blenheim :). Cheers, Walter PS Nearly forgot to mention that these wedges cannot be a permanent fixture, like riveted in place. The leading edges of the wing centre section (the bit between fuselage and nacelle) actually come off completely to enable servicing of the engine and aileron control runs that are mounted on the forward face of the front spar.

In essence, the Blenheim Mk I, IV and V share the same basic airframe aft of fuselage former 0.25, which is the one where the nose section attaches to. So the wing planform is identical between the three marks. As for the Mk V (Bristol Type 160), apart from the completely re-designed nose and a dorsal turret change from Bristol BI Mk IV to Bristol BX (the latter requiring a larger cut-out in the top fuselage as it was of larger diameter) other visible changes were: - Oil coolers repositioned in the wing leading edge (Beaufort and Beaufighter style) - Pitot tube repositioned from under the nose to under the port wing - "Apron" style single undercarriage door replaced by "clamshell" type doors fully enclosing the main wheels - Tail wheel replaced by a type which had a "knuckle" oleo strut - A much larger rudder trim tab, extending beyond the rudder trailing edge. Admiral, if you PM me your e-mail address I'll be happy to send you some more detailed Mk V info. Cheers, Walter

True, though they did replace the flat topped blind flying panel as used in the Mk I and Mk IV by the later rounded top one in the Mk V.

Hi Martin, There are quite a few differences as the Mk V nose was a complete redesign. From memory the only identical bits would be the pilot's seat, control column, rudder pedals and engine controls. If you'd care to PM me your e-mail address I'll be happy to send you some details. Cheers, Walter

Hi, As per the relevant Air Publication, the Blenheim had a De Havilland variable-pitch prop Type 4/3, D.I.S. No 19 of 10 ft 9 in diameter. The Lysander's prop, also De Havilland variable-pitch, is quoted as a D.I.S. No 15 of 11 ft 0 in diameter. What exactly D.I.S. refers to is to be found in Air Publication 1538 Vol I, of which I sadly don't have a copy. Anyway, Lizzie's prop is larger in diameter by 70mm if I converted correctly, which in 1/32nd scale is 2.19 mm. Cheers, Walter

Great photo, isn't it, I've got it in my Blenheim collection as well, found somewhere on the web ages ago. The fuel dump pipes make it a Mk IV, this had extra tanks in the outer wing sections which the Mk I didn't have (the tanks that is). For an emergency landing with full fuel load the contents of the outer tanks could be dumped. Would have to disagree with the gear legs being black though, they just look muddy/dirty to me :). The black visible through the openings in the nacelle side is indeed the main fuel tank. It is my understanding that self sealing fuel tanks were a reddish colour, if that's correct then this early Mk IV didn't have them fitted (yet). Happy to be corrected though. Cheers, Walter

Thank you Graham, Geoffrey and Paul for your valuable input! The message referrred to by Paul clearly answers my question. Could one then one also conclude that the few 2 Group Blenheim squadrons that participated in the "1000 Raids" in May and June 1942 were still carrying the Temperate Sea Scheme on their upper surfaces? Their undersurfaces received a coat of black distemper for those ops. Cheers, Walter

Another Blenheim question! From about April 1941 onwards 2 Group's Blenheim squadrons were heavily involved in anti-shipping ops. Stuart R. Scott in "Battle Axe Blenheims" mentions how 105 Sqn's aircraft were re-finished in Temperate Sea Scheme colours for this purpose. And in his "The Bristol Blenheim - A complete history", Graham Warner also describes how most of the 2 Group Blenheims had their camouflage changed from Temperate Land to Temperate Sea Scheme. Besides those anti-shipping ops however those 2 Group Blenheims were still employed on the occasional bombing trip to occupied Europe, and there were the "Circus", "Roadstead" and "Fringe" operations as well. Obviously the Temperate Sea Scheme would be less effective when flying over land so I was wondering if the squadrons involved would have held a number of aircraft in the Temperate Land Scheme for the operations other than anti shipping. Any thoughts on this matter would be welcomed. Cheers, Walter

From the photo's I've studied it would appear that the black finish for the undercarriage legs was only to be found on Mk I's, the Mk IV's legs being finished in silver paint. As for the wheel well and bomb bay colour's I'd agree with the others on interior green. Remember that a Blenheim's bomb doors (held closed by bungee cords) are opened by the falling bombs and snap shut again immediately after. Cheers, Walter

Hi Matt, it's the details for the Bristol B1 Mk IV turret you're after. If you'd care to pop me a PM with your e-mail address I'll gladly send you copies out of the related Air Publication. There's a bit more to it than a tiny seat and a couple of ammunition boxes, it is quite a complicated set-up really 😀. Cheers, Walter

Hi Tweener, Sure, PM me your e-mail address please and I will gladly send you those drawings. Cheers, Walter